Bonner, who has represented Alabama's 1st District for six terms since 2003, will become vice chancellor of government relations and economic development at Alabama. His sister, Judy Bonner, serves as president of the university.

"Bonner has been best known in Congress for helping his constituents and his work on the Appropriations Committee, the panel that allocates most federal funds. Through that committee, Bonner worked to get federal aid to states hard hit by Hurricane Katrina.

"Beyond Alabama, however, Bonner may best be remembered for service on the Ethics Committee when [New York Democrat Charles] Rangel was censured — the toughest form of punishment short of expulsion. Serving on the ethics committee has long been a thankless task for members of Congress because of its role in policing lawmakers. Bonner took the unusual step of criticizing then-Ethics Committee chairwoman Zoe Lofgren, D-Calif., for not scheduling Rangel's trial ahead of the November elections in 2010."

The Washington Post reports that potential Republican candidates for the vacant seat would "include state Sen. Bill Hightower, state Sen. Trip Pittman and 2010 gubernatorial candidate Bradley Byrne, who lost a runoff to [Gov. Robert] Bentley. The district is strongly Republican, giving Mitt Romney more than 60 percent of the vote in 2012."